A Work Commenced April 20 2023

Preamble

Product: Oberwerk SE 10 x 42 ED

Country of Manufacture: China

Chassis Material: Rubber Armoured Aluminium

Exit Pupil: 4.2mm

Field of View: 114m@1000m(6.5 angular degrees)

Eye Relief: 15mm(Useable)

Close Focus: 4m advertised, 4.39m measured

Coatings: Fully Broadband Multicoated

ED Glass: Yes

Waterproof: Yes

Nitrogen Purged: Yes

Weight: 872g measured

Accessories: Carry case, objective and rain guard(tetherable), lens cleaning cloth, test card, logoed and non-logoed neck straps.

Dimensions: 15 x 16.5cm

Warranty: 2 years

Price: $279.95

A few months back, I took the plunge and decided to order up one of the new binoculars offered by Oberwerk (see the preamble above). While I had heard great things about the company’s larger binoculars, I was genuinely intrigued when they brought out their SE series of smaller aperture Porro prism binoculars. The 8 x 32 SE has turned out to be something of a marvel; very bright, sharp, high-contrast images, a great big sweet spot and superb colour correction. But it didn’t end there. The same binocular is very well built and handles better than any other binocular I’ve had the pleasure to field test in this aperture class.. The 8 x 32 SE is the smallest binocular in this series, but my sustained attention to high-performance Porros stoked my interest in its larger sibling, the Oberwerk 10 x 42 SE. Intriguingly, it was being offered for only about $30 more than the 32mm model, so I ordered a unit up for testing and evaluation.

Like the 8 x 32 package, the 10 x 42 arrived within a week of me ordering it. Everything was well packed; the binocular with attached rain guards, the test card, neck straps and a fine soft padded case. Amazingly, this bigger brother of the 8 x 32 SE only weighs about 80g more. And just like the smaller Oberwerk, it’s built like a proverbial tank, with a thick, grippy rubber armouring surrounding the aluminium chassis.

Everything worked smoothly; the central focus wheel, the right eye dioptre, the twist up eye cups with their comfortable eye relief. The only significant difference from the smaller model is that the objective lenses are not as deeply recessed. But that’s only because the extent of the recession of the 8x 32 SE objectives is truly cavernous!

Next, the optics. Just like the 8 x 32 model, the 10 x 42 shows no internal reflections when pointed at a bright artificial light source. Taking a shot of the exit pupils showed very nice results, maybe not quite as nice as those found in the 32mm model but very good nonetheless.

So what is it like to look through?

In a word: terrific!

On the afternoon it arrived, I quickly attached the neck strap and took myself off up to Culcreuch Pond to have a gander at the bird life. I was greeted by no less than three Cormorants, all perched on the fallen tree at the north edge of the pond. The generous field of view framed the birds perfectly. This is the tree I most often judge the size of the sweet spot during daylight hours as the trunk spans the field from edge to edge. I could instantly see that this was a high-quality optic with beautiful details on their feathers and long slender beaks coming through. I could also see that there was only a very modest amount of softening of the image at the field stops. That said, having experienced a few other 10x glasses with 6.5+ degree fields, the portal seemed a little short of what I expected. More on this later.

With leaden skies and the light rapidly failing, I didn’t think I’d see much more of interest that day, but as I was walking down the country road on the castle drive I heard the sound of a Woodpecker and quickly aimed the Oberwerk 10 x 42 SE as best I could towards some trees in an open field. Scanning carefully, I caught sight of a Great Spotted Woodpecker busy hunting for insects. And, as if by magic, a beautiful sunbeam broke through the clouds, illumining the tree with warm, radiant light. The striking colours of the bird – black, white and red -came to life. But then, from out of nowhere, a second Great Spotted Woodpecker emerged from behind another branch! I had never seen anything quite like this before! The view was razor sharp, the colours pure and intense, the stereopsis in the middle distance enhanced by the 10x boost producing an unforgettable visual extravaganza. The first bird took to flight after about 45 seconds of viewing it, the second followed suit shortly thereafter. Then the sunbeam disappeared, and I was back to sullen grey rainclouds serving as the backdrop to the tree top.

Still, the target served as an excellent test bed to see how well the optic was corrected for chromatic aberration. Once again, the Oberwerk 10 x 42 SE delivered in spades! Did it reach the sheer excellence of the 32mm unit? No, not quite, but it was very close.

I had anticipated that the perfect colour correction of the smaller 8 x 32 unit would be considerably more difficult to pull off with that higher magnification and greater light grasp of the larger 42mm objectives. But the results were excellent! I detected only a trace of lateral colour right out near the field stops and none within the sweet spot under these harsh lighting conditions. Indeed, on subsequent days with varying quality light, I became convinced that this binocular was well above average, even compared with other glasses endowed with well-executed ED glass objectives. Those who are sensitive to CA will be delighted with this optic. It’s just not an issue – quite a result, actually, for a big 10 x 42 like this.

Both the 8 x 32 and 10 x 42 Oberwerk Porros exhibit exceptional suppression of glare, which can only be achieved by a combination of high-quality coatings, good baffling and decently recessed objectives. Glassing into strongly backlit scenes presents little problem for these glasses. This extraordinary glare suppression adds to the visual punch of the images they serve up. Close focus on the 10 x 42 was measured to be 4.39m, a little longer than advertised but of no consequence to me, as this glass was designed for observing in the long to middle distance. Eye glass wearers will also be able to view the entire field thanks to the generous useable eye relief on these models.

The Oberwerk SE 10 x 42 is very comfortable to handle, despite its heftiness. Indeed, as I extended my glassing sessions with both these instruments, I came to appreciate that I could actually get slightly steadier images from them compared with my smaller, lighter glasses, so long as I didn’t over do it time wise, when muscular fatigue sets in. Studies I’ve read suggest hand-induced tremors manifest in the low frequency range, between 3 and 10Hz, and further indicate that using heavier glasses will introduce enough inertia to dampen these oscillations significantly. I noted this first with the smaller 8 x 32 SE comparing it with my lighter 8 x 30 Nikon E II, but it’s also true of the larger 10 x 42 unit, having done similar tests comparing it to my beloved Nikon E 10 x 35 WF.

So how did these glasses compare optically? The Nikon has the wider field of view at 6.6 angular degrees. In bright light, the views are very comparable, that is, excellent, although I could see a good deal more lateral colour in the Nikon glass(non-ED) compared with the Oberwerk. In dull light conditions, such as near sunset or on heavily overcast days, the Oberwerk serves up significantly better images; they’re brighter and display no glare, which can sometimes be an issue for the Nikon. The Oberwerk also shows much milder pincushion distortion in the outer field compared with the Nikon too.  

Adventures under the Stars

I can pretty much instantly tell if a binocular is mis-collimated in daylight tests, but I usually also test alignment of the barrels under the stars. By defocusing the bright star Arcturus using the right eye dioptre ring, I could see the focused star image from the left barrel was perfectly centred inside the defocused anulus of the right barrel image, so all was well. Centring the same star and moving it progressively further off axis, I was delighted to see that it remained a sharp pinpoint to about 80 per cent of the way to the field stop, after which the star showed the tell-tale signs of mild field curvature and some astigmatism. That said, even at the field stops, the star was only moderately deformed and didn’t present as an issue. Indeed, I consider that excellent performance for a binocular that lacks field flatteners.

In my next test, I mounted the Oberwerk SE 10 x 42 ED on a tripod and centred Regulus in Leo, located some 12 degrees from the celestial equator and near my local meridian to conduct timing measurements of how long it took the star to reach the field stop. These times(in seconds) were doubled and then plugged into a standard astronomical formula requiring the cosine of the star’s declination, to measure field size. The arithmetic mean of such timings yielded a result of 6.44 angular degrees, a little less than the advertised 6.5 degrees, which I had suspected whilst comparing the Oberwerk to my Nikon E 10 x 35. These tests were carried out during a string of cold nights, where the temperatures fell below zero in the wee small hours of early April. This afforded an excellent opportunity to test another claim made by Oberwerk; fog proofing. Exposing the instrument to the cold for a couple of hours, I then brought it inside to a warm living room where the external optics fogged up, as expected. The inside of the instrument remained clear and fog free however, indicating that these instruments were indeed immune to internal fogging. Apparently, Oberwerk has been successfully doing this for well over a decade, as I came across a reference made by Phil Harrington who discussed this fact in his 2007 Star Ware.

Enjoying a long spell of settled clear weather, with blue skies by day and clear frosty nights, I enjoyed several astronomical vigils with this binocular. Handholding is OK for quick looks, but to get the most out of the instrument I mounted it on my trusty monopod, with a ball & socket head for increased stability and maximum manoeuvrability. On the evening of April 10 at 9.15pm local time, I spied an amazing apparition in the late evening twilight sky; the bright planet Venus and the Pleiades were framed within the same field of view! Venturing out about half an hour later with the sky fully dark, I was enthralled to see the same view, only this time many more stars were visible within the cluster and brilliant white Venus shining through the darkness, creating an unforgettable visual spectacle. Lying comfortably on a zero-gravity chair, I enjoyed spellbinding views of Praesepe and the Beehive Cluster at its heart, the sprawling stellar association known as the Coma Berenices Cluster(Melotte 111), the Alpha Persei Association and the Double Cluster, now sinking lower into my northern skies. I’ve said it before and I’ll say it again, there’s something very special about the star images Porro prism binoculars serve up compared with their roof prism counterparts. To my eye, they appear more pinpoint and intense, more aesthetically pleasing. What’s more, I’ve noted the greater contrast induced by smaller exit pupils(< 5mm). The sky appears noticeably darker, intensifying the images of stars and faint nebulae. That’s also why the Nikon E 10 x 35 WF is such a lovely stargazing glass!

Because summer twilight sets in from about mid-May to the end of July this far north, I often do some of my summer observing in the wee small hours of late April mornings when the sky is still properly dark, and the traditional summer constellations rise high in the eastern sky. I had the opportunity to observe the Milky Way through Cygnus and Lyra, soaking up the beautiful, pristine star colours each field of view afforded. The region around Sadr was particularly memorable, as was the striking colour contrast binocular double 31 Cygni. Brilliant Vega was pure white as the driven snow and nearby Epsilon 1 & 2 Lyrae were easy pickings for this binocular. The great globular cluster in Hercules, M13, was a striking sight in this excellent 10  x 42, as was Albireo(Beta Cygni), which was nicely resolved using a steady monopod into comely orange and blue components.

Conclusions & Recommendations

The Porro prism binocular revolution continues apace, and Oberwerk has positioned itself at the cutting edge of this movement with the marketing of these new instruments. Both the Oberwerk SE 8 x 32 and 10 x 42 proved to be excellent performers by day, and also after dark. Their no-nonsense, robust build quality and great optical performance will delight most anyone who views with them. Indeed, the experiences I’ve had with these instruments make me seriously question why anyone would want to consider roof prism binoculars costing up two or three times more than these instruments for little or no gain in performance. It just doesn’t cut the mustard! Both represent exceptional value for money in today’s market and will provide years of reliable performance to birdwatchers and stargazers alike.

Needless to say, you’ll be hearing more about my adventures with both these instruments in the months and years to come!

So, watch this space!

Neil English is the author of seven books in amateur and professional astronomy. His 8^th title on binoculars hits the shelves later this year.

De Fideli.